title: Incidence of cancer in a cohort of Spanish patients with systemic lupus erythematosus.
abstract: OBJECTIVE
  To determine the incidence and prevalence of cancer in a cohort of patients with systemic lupus erythematosus (SLE) and identify associated risk factors.
  
  
  METHODS
  The study comprised a dynamic cohort of SLE patients (November 1989 to December 2006) at a tertiary referral centre. An adjusted external control from the hospital tumour registry was used.
  
  
  RESULTS
  The study included 175 SLE patients (90% women), with a mean time at risk of 1370.5 patient-years. Fourteen women (8%) died, mainly from cardiovascular events. No patient died due to malignancy. We found 35 tumours in 28 patients, 25 of them after the diagnosis of SLE, of which 5 were malignant. The rate of benign tumours was 14.6/1000 patient-years (95% CI, 8.9-22.5) and of malignant tumours 3.6/1000 patient-years (95% CI, 1.5-8.8), with a crude incidence odds ratio for malignant tumours of 3.5 (95% CI, 1.5-7.9). However, this significance was lost after standardizing the rates. Concerning associated risk factors, differences were found in the mean erythrocyte sedimentation rate [HR 1.4 (1.1-1.7)], and the presence of thrombosis [HR 6.9 (1.49-41.2)], especially arterial thrombosis.
  
  
  CONCLUSIONS
  We found a crude incidence rate of cancer that was almost four times greater in our SLE patients as compared with the expected rate in the hospital area of western Malaga.
authors.affiliation: Hospital Universitario "Virgen de la Victoria", Malaga, Spain. Electronic address: ahidalgoconde@gmail.com.
authors.forename: Ana
authors.initials: A
authors.lastname: Hidalgo-Conde
authors.forename: Manuel
authors.initials: M
authors.lastname: de Haro Liger
authors.forename: Manuel
authors.initials: M
authors.lastname: Abarca-Costalago
authors.forename: Martina
authors.initials: M
authors.lastname: Álvarez Pérez
authors.forename: Pedro
authors.initials: P
authors.lastname: Valdivielso-Felices
authors.forename: Pedro
authors.initials: P
authors.lastname: González-Santos
authors.forename: Antonio
authors.initials: A
authors.lastname: Fernández-Nebro
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D015994:Incidence; D008180:Lupus Erythematosus, Systemic / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology
keywords: Cancer; Cáncer; Incidence; Incidencia; Lupus eritematoso sistémico; Malignancy; Malignidad; Systemic lupus erytematosus